International Database for Barley Genes and Barley Genetic Stocks

BGS 59, Grandpa 1, gpa1

BGN  45:91
Stock number: BGS 59
Locus name: Grandpa 1
Locus symbol: gpa1

Previous nomenclature and gene symbolization:

Grandpa = gp (3).
Grandpa 2 = gp2 (7, 8).


Monofactorial recessive (3).
Located in chromosome 2HL (6, 7); gpa1.a is about 24.5 cM distal from the lig1 (liguleless 1) locus (5); gpa1.a is associated with SNP markers 2_0069 to 10085 (positions 179.99 to 247.86 cM) in 2H bins 11 to 14 of the Bowman backcross-derived line BW397 (1).


Seedlings display a pattern of transverse of alternating white and green bands on the first, second, and occasionally the third foliage leaves. Plants have a slightly pale green color prior to heading. Grandpa plants are sensitive to flooding and produce an albino flag leaf, peduncle, and spike (5). Plants are viable in the field, but kernels are thin and yields are low (6). Compared to Bowman, plants of the Bowman backcross-derived line for gpa1.b, BW397, were very sensitive to stressed environments. BW397 plants headed 4 to 10 days later than Bowman and were 50 to 75% as tall. Kernels were thin, 3.18 vs. 3.86 mm, and weighed 50 to 80% of Bowman kernels. Grain yields of BW397 were 10 to 30% of those for Bowman (2).

Origin of mutant:

A spontaneous mutant in Lyallpur (PI 57954) isolated by GA Wiebe (4).

Mutational events:

gpa1.a (CIho 6027, GSHO 519) in Lyallpur (PI 57954) (4); gpa1.b (gp2) (GSHO 1379) in Montcalm (CIho 7149) (5, 7, 8).

Mutant used for description and seed stocks:

gpa1.b (GSHO 1379) in Montcalm; gpa1.a in Bowman (PI 483237)*7 (GSHO 1934, BW397, NGB 22147).


1. Druka, A., J. Franckowiak, U. Lundqvist, N. Bonar, J. Alexander, K. Houston, S. Radovic, F. Shahinnia, V. Vendramin, M. Morgante, N. Stein, and R. Waugh. 2010. Genetic dissection of barley morphology and development. Plant Physiol. 155:617-627.
2. Franckowiak, J.D. (Unpublished).
3. Immer, F.R., and M.T. Henderson. 1943. Linkage studies in barley. Genetics 28:419-440.
4. Martini, M.L., and H. V. Harlan. 1942. Barley freaks. J. Hered. 33:339-343.
5. Matchett, R.W., H.G. Nass, and D.W. Robertson. 1971. Inheritance and linkage studies with the grandpa gene in barley, Hordeum vulgare L. Can. J. Genet. Cytol. 13:489-498.
6. Matchett, R.W., B.M. Pollock, and D.W. Robertson. 1968. The "grandpa" gene: A chlorophyll mutation in Hordeum species. J. Hered. 59:279-282.
7. Tsuchiya, T. 1971. Trisomic analysis of grandpa 2 (gp2). Barley Genet. Newsl. 1:62.
8. Walker, G.W.R., J. Dietrich, R. Miller, and K.J. Kasha. 1963. Recent barley mutants and their linkages II. Genetic data for further mutants. Can. J. Genet. Cytol. 5:200-219.


T. Tsuchiya and T.E. Haus. 1971. Barley Genet. Newsl. 1:119.


T. Tsuchiya. 1980. Barley Genet. Newsl.10:107.
J.D. Franckowiak. 1997. Barley Genet. Newsl. 26:95.
J.D. Franckowiak. 2014. Barley Genet. Newsl. 44:62-63.
J.D. Franckowiak. 2015. Barley Genet. Newsl. 45:91-92.